1. Field of the Invention
The present invention relates generally to operating mechanisms and more particularly to a switch-operating mechanism including a charging arrangement that sequentially charges the energy storage means of the operating mechanism during an initial charging cycle before any switch-opening or switch-closing operation is performed.
2. Description of the Related Art
Various operating mechanisms are utilized to operate switches and the like between open and closed positions. In particular, operating mechanisms are desirable for switch applications wherein operating energy is stored for selectively closing a switch and for immediately thereafter being capable of opening the switch as required.
A first variety of operating mechanism provides for the charging of an opening spring during the switch closing operation. Examples of this type of mechanism are disclosed in the following U.S. Pat. Nos.: 4,453,056; 4,121,077; 4,105,878; 3,898,409; 3,845,263; 3,835,277; 3,784,764; 3,728,508 and 3,600,541. This type of operating mechanism requires a higher-capacity closing spring to perform the functions of both closing the switch and charging the opening spring. The requirement of a higher-capacity closing spring is, of course, undesirable since it also requires higher-capacity latching, driving and supporting arrangements.
Another variety of operating mechanism requires the detaching of the closing spring from the operating member during switch opening. This type of operating mechanism requires a relatively complex arrangement for the required detaching of the closing spring. U.S. Pat. No. 3,876,847 discloses an arrangement that sequentially charges the closing spring and then the opening spring. A spring charging handle is rotated in a first direction to charge the closing spring and is then rotated in the opposite direction to charge the opening spring. The arrangement includes the detaching of the closing spring during switch opening.
Operating mechanisms that avoid some of the drawbacks of the aforementioned approaches are disclosed in U.S. Pat. No. 4,124,790 and U.S. patent application Ser. Nos. 721,613 filed on Apr. 10, 1985 (now U.S. Pat. No. 4,578,551), in the name of C. H. Lin and No. 721,617 filed on Apr. 10, 1985 in the names of W. J. Hall et al., (now U.S. Pat. No. 4,636,602), both applications being assigned to the same assignee as the present application. These mechanisms provide for charging the opening and closing springs simultaneously and do not require the detaching of the closing spring during switch opening. However, the configuration of U.S. Pat. No. 4,124,790 is complex and is neither suitable nor desirable for many applications. For example, a switch operating drive lever assembly 69 is only indirectly latched through a collapsable toggle lever assembly 71. Further, the arrangement to latch the toggle lever assembly 71 is complex and requires a latching element that operates against moving latching surfaces. Accordingly, the arrangement in U.S. Pat. No. 4,124,790 includes complex, indirect latching and a complex arrangement to transmit force and movement from the drive lever member 123 to the switch operating member 77. However, these arrangements still require high peak forces during charging.
While the aforementioned arrangements may be generally useful and satisfactory for their intended use, it would be desirable to provide an operating mechanism with an improved charging arrangement that reduces the peak forces required during charging and that does not require the detaching of any spring during operation.